THE PHILIPPINE 



Journal of Science 



B. Medical Sciences 



Vol. VI APEIL, 1911 No. 2 



INVESTIGATION ON THE ACTION OF THE TROPICAL SUN 



ON MEN AND ANIMALS. 



By Hans Aron. 



{From the Physiological Laboratory, College of Medicine and Surgery, University 

 of the Philippines, Manila, P. I.) 



The meteorologic conditions which surround us, such as temperature, 

 humidity, barometric pressure and the movements in the atmosphere, 

 all of which, to a great extent, are controlled by the radiation of the 

 sun, are included under the designation of climate. Each of these factors 

 of environment has its characteristic influence upon the life functions of 

 living organisms. We can, on the one hand, study the influence of 

 differing temperatures, humidities, and movements and pressures of the 

 air on men and animals in modern respiration calorimeters without the 

 need of conducting the work in a particular climate. Eubner,'- especially, 

 has carried on such work. But, on the other hand, the action of the 

 sun of a given latitude can not be reproduced artificially. 



The radiant energy of the sun which reaches the atmosphere is in 

 part absorbed while passing through the latter, and this < absorption, 

 other conditions being equal, should be smaller the less deep the absorb- 

 ing layer. If conditions, such as layers of the atmosphere of unequal 

 density which would tend to refract the rays, do not intervene, and 

 again, if all other conditions are equal, the absorption is smallest during 

 the vertical incidence of the rays; that is, when the sun is in the zenith. 



"■Arch. f. Eyg. (1894), 20, 309-312, 345-364, 365-371; (1895), 23, 87, 13-43; 

 (1900), 38, 120-159. Die Gesetze des Energieverbrauches bei der Ernabrung, 

 Leipzig- Wien (1902). 



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